6th Gen ('00-'05): coolant leak
I found this post on the forum. Hope this helps.................
I'm surprised with as common as this job is, we don't have a good how to guide in the tech info section 
The job is easy, especially on a 3800. I've done it a few times. A lot of the stuff I feel is pretty straight forward. There are a lot of videos on YouTube about this, here's one I found that looked "start to finish". Just take your time.
LINK---> GM 3.8 Intake Manifold replacement. Removal the fast way WITH NOTES - YouTube
Recommendations:
- Get the Fel Pro metal core LIM gasket kit and doesn't matter much on the UIM gasket kit (I believe I've used a Dorman most of the time).
- Get the torque specs for the lower and upper intake (especially the upper, it's plastic, over-torquing means damage).
- I pulled the UIM off with the T-body attached. This is handy to inspect the UIM! The UIM failure is where the EGR "stove pipe" is (the pipe is literally a piece of pipe sticking up on the UIM, I believe Dorman gives a narrow pipe replacement to ward off UIM damage). On two sides of the UIM are coolant ports, they take coolant in and out of the T-body. Place a finger over one port, blow compressed air in the other, watch around the opening for the stove pipe for coolant or air to blow throw. If so, the UIM has gotten brittle and damaged (common UIM failure that causes coolant to enter the cylinders). Frame 11:07 the guy points the EGR opening on the UIM.
- If the UIM is damaged, you have two options. One is replace the UIM. The other (and cheaper), tap the coolant ports on the LIM, plug them. I used stainless steel set scres, I've soon others use brass plumbing plugs (I think the brass plugs are better, NTP threwads are finer then the ones on my stainless plugs). For extra insurance, JB weld the coolant ports shut on the UIM.
- As mentioned, change the T-body gasket (should come with the UIM gasket kit in most cases).
- Even though the guy does the job without pulling the tensioner assembly and the alt, I recommend doing it and change the coolant elbows while you are at it (Dorman now makes aluminum elbows, gets rid of another plastic failure point).
- Clean as much as you can. The cleaner things are, better the job is AND in some cases, improves car performance.
I think that's about it. I hope it helps!
The job is easy, especially on a 3800. I've done it a few times. A lot of the stuff I feel is pretty straight forward. There are a lot of videos on YouTube about this, here's one I found that looked "start to finish". Just take your time.
LINK---> GM 3.8 Intake Manifold replacement. Removal the fast way WITH NOTES - YouTube
Recommendations:
- Get the Fel Pro metal core LIM gasket kit and doesn't matter much on the UIM gasket kit (I believe I've used a Dorman most of the time).
- Get the torque specs for the lower and upper intake (especially the upper, it's plastic, over-torquing means damage).
- I pulled the UIM off with the T-body attached. This is handy to inspect the UIM! The UIM failure is where the EGR "stove pipe" is (the pipe is literally a piece of pipe sticking up on the UIM, I believe Dorman gives a narrow pipe replacement to ward off UIM damage). On two sides of the UIM are coolant ports, they take coolant in and out of the T-body. Place a finger over one port, blow compressed air in the other, watch around the opening for the stove pipe for coolant or air to blow throw. If so, the UIM has gotten brittle and damaged (common UIM failure that causes coolant to enter the cylinders). Frame 11:07 the guy points the EGR opening on the UIM.
- If the UIM is damaged, you have two options. One is replace the UIM. The other (and cheaper), tap the coolant ports on the LIM, plug them. I used stainless steel set scres, I've soon others use brass plumbing plugs (I think the brass plugs are better, NTP threwads are finer then the ones on my stainless plugs). For extra insurance, JB weld the coolant ports shut on the UIM.
- As mentioned, change the T-body gasket (should come with the UIM gasket kit in most cases).
- Even though the guy does the job without pulling the tensioner assembly and the alt, I recommend doing it and change the coolant elbows while you are at it (Dorman now makes aluminum elbows, gets rid of another plastic failure point).
- Clean as much as you can. The cleaner things are, better the job is AND in some cases, improves car performance.
I think that's about it. I hope it helps!
Last edited by KCFITZ78; Dec 21, 2015 at 11:03 PM.
Joined: Nov 2012
Posts: 154
I just noticed my engine coolant is very low, been losing oil for awhile now. Since i replaced the elbows, and have a thick dogsh*t like clump on my rad cap, I am guessing I have a LIM leak. not looking forward to replacing it, engines are the one thing that does scare me to mess with, though 1k is 1k.
What kit is preferred to fix this issue
1- FEL-PRO MS98014T {#MIS16203A} PermaDryPlus®; Intake Manifold Gasket Set
2- ACDELCO 89017816 GM Original Equipment
What kit is preferred to fix this issue
1- FEL-PRO MS98014T {#MIS16203A} PermaDryPlus®; Intake Manifold Gasket Set
2- ACDELCO 89017816 GM Original Equipment
Last edited by xpage; Jan 24, 2016 at 11:08 PM.
Joined: Mar 2014
Posts: 49
FYI, here is the kit your looking for ND THE PRICE IS CHEAP//////
Intake Manifold Gasket Set ACDELCO 89017816 GM | eBay
Intake Manifold Gasket Set ACDELCO 89017816 GM | eBay
Monte Of The Month -- January 2016
Joined: Feb 2013
Posts: 2,293
From: Pacific NW
IMO, the Fel-Pro gasket set is better. It has the aluminum reinforced core that resists meltdown. To my knowledge the ACDelco ones are still all plastic and eventually end up with the same problem as the original. Here's the Fel-Pro: Engine Intake Manifold Gasket Set FEL Pro MS 98014 T | eBay
I would also replace the Upper intake Manifold at the same time. here's the Dorman kit: http://www.ebay.com/itm/DORMAN-615-1...ZRpQbt&vxp=mtr
I would also replace the Upper intake Manifold at the same time. here's the Dorman kit: http://www.ebay.com/itm/DORMAN-615-1...ZRpQbt&vxp=mtr
Last edited by plumbob; Jan 25, 2016 at 09:58 AM.